Allows to choose which attributes should be whitelisted for mass updating and thus prevent accidentally exposing that which shouldn’t be exposed. Provides two methods for this purpose: require and permit. The former is used to mark parameters as required. The latter is used to set the parameter as permitted and limit which attributes should be allowed for mass updating.
params = ActionController::Parameters.new({ person: { name: 'Francesco', age: 22, role: 'admin' } }) permitted = params.require(:person).permit(:name, :age) permitted # => {"name"=>"Francesco", "age"=>22} permitted.class # => ActionController::Parameters permitted.permitted? # => true Person.first.update!(permitted) # => #<Person id: 1, name: "Francesco", age: 22, role: "user">
It provides two options that controls the top-level behavior of new instances:
permit_all_parameters
- If it's true
, all the
parameters will be permitted by default. The default is false
.
action_on_unpermitted_parameters
- Allow to control the
behavior when parameters that are not explicitly permitted are found. The
values can be :log
to write a message on the logger or
:raise
to raise ActionController::UnpermittedParameters
exception. The default value is :log
in test and development
environments, false
otherwise.
Examples:
params = ActionController::Parameters.new params.permitted? # => false ActionController::Parameters.permit_all_parameters = true params = ActionController::Parameters.new params.permitted? # => true params = ActionController::Parameters.new(a: "123", b: "456") params.permit(:c) # => {} ActionController::Parameters.action_on_unpermitted_parameters = :raise params = ActionController::Parameters.new(a: "123", b: "456") params.permit(:c) # => ActionController::UnpermittedParameters: found unpermitted keys: a, b
ActionController::Parameters
is inherited from
ActiveSupport::HashWithIndifferentAccess
, this means that you
can fetch values using either :key
or
"key"
.
params = ActionController::Parameters.new(key: 'value') params[:key] # => "value" params["key"] # => "value"
Never raise an UnpermittedParameters exception because of these params are present. They are added by Rails and it's of no concern.
This is a white list of permitted scalar types that includes the ones supported in XML and JSON requests.
This list is in particular used to filter ordinary requests, String goes as first element to quickly short-circuit the common case.
If you modify this collection please update the API of permit
above.
Returns a new instance of ActionController::Parameters
. Also,
sets the permitted
attribute to the default value of
ActionController::Parameters.permit_all_parameters
.
class Person < ActiveRecord::Base end params = ActionController::Parameters.new(name: 'Francesco') params.permitted? # => false Person.new(params) # => ActiveModel::ForbiddenAttributesError ActionController::Parameters.permit_all_parameters = true params = ActionController::Parameters.new(name: 'Francesco') params.permitted? # => true Person.new(params) # => #<Person id: nil, name: "Francesco">
# File lib/action_controller/metal/strong_parameters.rb, line 123 def initialize(attributes = nil) super(attributes) @permitted = self.class.permit_all_parameters end
Returns a parameter for the given key
. If not found, returns
nil
.
params = ActionController::Parameters.new(person: { name: 'Francesco' }) params[:person] # => {"name"=>"Francesco"} params[:none] # => nil
# File lib/action_controller/metal/strong_parameters.rb, line 270 def [](key) convert_hashes_to_parameters(key, super) end
Returns an exact copy of the ActionController::Parameters
instance. permitted
state is kept on the duped object.
params = ActionController::Parameters.new(a: 1) params.permit! params.permitted? # => true copy_params = params.dup # => {"a"=>1} copy_params.permitted? # => true
# File lib/action_controller/metal/strong_parameters.rb, line 312 def dup super.tap do |duplicate| duplicate.instance_variable_set :@permitted, @permitted end end
Returns a parameter for the given key
. If the key
can't be found, there are several options: With no other arguments, it
will raise an ActionController::ParameterMissing
error; if
more arguments are given, then that will be returned; if a block is given,
then that will be run and its result returned.
params = ActionController::Parameters.new(person: { name: 'Francesco' }) params.fetch(:person) # => {"name"=>"Francesco"} params.fetch(:none) # => ActionController::ParameterMissing: param not found: none params.fetch(:none, 'Francesco') # => "Francesco" params.fetch(:none) { 'Francesco' } # => "Francesco"
# File lib/action_controller/metal/strong_parameters.rb, line 285 def fetch(key, *args) convert_hashes_to_parameters(key, super) rescue KeyError raise ActionController::ParameterMissing.new(key) end
Returns a new ActionController::Parameters
instance that
includes only the given filters
and sets the
permitted
attribute for the object to true
. This
is useful for limiting which attributes should be allowed for mass
updating.
params = ActionController::Parameters.new(user: { name: 'Francesco', age: 22, role: 'admin' }) permitted = params.require(:user).permit(:name, :age) permitted.permitted? # => true permitted.has_key?(:name) # => true permitted.has_key?(:age) # => true permitted.has_key?(:role) # => false
Only permitted scalars pass the filter. For example, given
params.permit(:name)
:name
passes it is a key of params
whose
associated value is of type String
, Symbol
,
NilClass
, Numeric
, TrueClass
,
FalseClass
, Date
, Time
,
DateTime
, StringIO
, IO
,
+ActionDispatch::Http::UploadedFile+ or +Rack::Test::UploadedFile+.
Otherwise, the key :name
is filtered out.
You may declare that the parameter should be an array of permitted scalars by mapping it to an empty array:
params.permit(tags: [])
You can also use permit
on nested parameters, like:
params = ActionController::Parameters.new({ person: { name: 'Francesco', age: 22, pets: [{ name: 'Purplish', category: 'dogs' }] } }) permitted = params.permit(person: [ :name, { pets: :name } ]) permitted.permitted? # => true permitted[:person][:name] # => "Francesco" permitted[:person][:age] # => nil permitted[:person][:pets][0][:name] # => "Purplish" permitted[:person][:pets][0][:category] # => nil
Note that if you use permit
in a key that points to a hash, it
won't allow all the hash. You also need to specify which attributes
inside the hash should be whitelisted.
params = ActionController::Parameters.new({ person: { contact: { email: 'none@test.com', phone: '555-1234' } } }) params.require(:person).permit(:contact) # => {} params.require(:person).permit(contact: :phone) # => {"contact"=>{"phone"=>"555-1234"}} params.require(:person).permit(contact: [ :email, :phone ]) # => {"contact"=>{"email"=>"none@test.com", "phone"=>"555-1234"}}
# File lib/action_controller/metal/strong_parameters.rb, line 247 def permit(*filters) params = self.class.new filters.flatten.each do |filter| case filter when Symbol, String permitted_scalar_filter(params, filter) when Hash then hash_filter(params, filter) end end unpermitted_parameters!(params) if self.class.action_on_unpermitted_parameters params.permit! end
Sets the permitted
attribute to true
. This can be
used to pass mass assignment. Returns self
.
class Person < ActiveRecord::Base end params = ActionController::Parameters.new(name: 'Francesco') params.permitted? # => false Person.new(params) # => ActiveModel::ForbiddenAttributesError params.permit! params.permitted? # => true Person.new(params) # => #<Person id: nil, name: "Francesco">
# File lib/action_controller/metal/strong_parameters.rb, line 150 def permit! each_pair do |key, value| convert_hashes_to_parameters(key, value) self[key].permit! if self[key].respond_to? :permit! end @permitted = true self end
Returns true
if the parameter is permitted, false
otherwise.
params = ActionController::Parameters.new params.permitted? # => false params.permit! params.permitted? # => true
# File lib/action_controller/metal/strong_parameters.rb, line 134 def permitted? @permitted end
Ensures that a parameter is present. If it's present, returns the
parameter at the given key
, otherwise raises an
ActionController::ParameterMissing
error.
ActionController::Parameters.new(person: { name: 'Francesco' }).require(:person) # => {"name"=>"Francesco"} ActionController::Parameters.new(person: nil).require(:person) # => ActionController::ParameterMissing: param not found: person ActionController::Parameters.new(person: {}).require(:person) # => ActionController::ParameterMissing: param not found: person
# File lib/action_controller/metal/strong_parameters.rb, line 172 def require(key) self[key].presence || raise(ParameterMissing.new(key)) end
Returns a new ActionController::Parameters
instance that
includes only the given keys
. If the given keys
don't exist, returns an empty hash.
params = ActionController::Parameters.new(a: 1, b: 2, c: 3) params.slice(:a, :b) # => {"a"=>1, "b"=>2} params.slice(:d) # => {}
# File lib/action_controller/metal/strong_parameters.rb, line 298 def slice(*keys) self.class.new(super).tap do |new_instance| new_instance.instance_variable_set :@permitted, @permitted end end
# File lib/action_controller/metal/strong_parameters.rb, line 400 def array_of_permitted_scalars?(value) if value.is_a?(Array) value.all? {|element| permitted_scalar?(element)} end end
# File lib/action_controller/metal/strong_parameters.rb, line 406 def array_of_permitted_scalars_filter(params, key) if has_key?(key) && array_of_permitted_scalars?(self[key]) params[key] = self[key] end end
# File lib/action_controller/metal/strong_parameters.rb, line 319 def convert_hashes_to_parameters(key, value) if value.is_a?(Parameters) || !value.is_a?(Hash) value else # Convert to Parameters on first access self[key] = self.class.new(value) end end
# File lib/action_controller/metal/strong_parameters.rb, line 328 def each_element(object) if object.is_a?(Array) object.map { |el| yield el }.compact elsif object.is_a?(Hash) && object.keys.all? { |k| k =~ /\A-?\d+\z/ } hash = object.class.new object.each { |k,v| hash[k] = yield v } hash else yield object end end
# File lib/action_controller/metal/strong_parameters.rb, line 413 def hash_filter(params, filter) filter = filter.with_indifferent_access # Slicing filters out non-declared keys. slice(*filter.keys).each do |key, value| return unless value if filter[key] == EMPTY_ARRAY # Declaration { comment_ids: [] }. array_of_permitted_scalars_filter(params, key) else # Declaration { user: :name } or { user: [:name, :age, { address: ... }] }. params[key] = each_element(value) do |element| if element.is_a?(Hash) element = self.class.new(element) unless element.respond_to?(:permit) element.permit(*Array.wrap(filter[key])) end end end end end
# File lib/action_controller/metal/strong_parameters.rb, line 384 def permitted_scalar?(value) PERMITTED_SCALAR_TYPES.any? {|type| value.is_a?(type)} end
# File lib/action_controller/metal/strong_parameters.rb, line 388 def permitted_scalar_filter(params, key) if has_key?(key) && permitted_scalar?(self[key]) params[key] = self[key] end keys.grep(/\A#{Regexp.escape(key)}\(\d+[if]?\)\z/) do |k| if permitted_scalar?(self[k]) params[k] = self[k] end end end
# File lib/action_controller/metal/strong_parameters.rb, line 353 def unpermitted_keys(params) self.keys - params.keys - NEVER_UNPERMITTED_PARAMS end
# File lib/action_controller/metal/strong_parameters.rb, line 340 def unpermitted_parameters!(params) unpermitted_keys = unpermitted_keys(params) if unpermitted_keys.any? case self.class.action_on_unpermitted_parameters when :log name = "unpermitted_parameters.action_controller" ActiveSupport::Notifications.instrument(name, keys: unpermitted_keys) when :raise raise ActionController::UnpermittedParameters.new(unpermitted_keys) end end end